There are several things that distinguish the truly great players from everyone else online. These would be:

1) Ability to read other players.

2) Ability to analyze situations.

3) Ability to exploit situations.

If you are the typical weak/tight player online, you will probably win a tournament from time to time. However, you will need everything to go right for you in order to win. You will need to win every race, and you will need for your big hands to hold up.

The difference between these players and the great players is that the great players accumulate enough chips by exploiting situations so that they can lose big hands and still not be out of the tournament.

The ability to read your opponents is of the utmost importance if you want to be successful. This comes strictly from experience. You need to watch every hand, even the ones that you aren't involved in. When you are playing, you need to be asking these types of questions: does this player usually raise with air? Is this playing constantly raising on the button with nothing? Is this player weak/tight, folding hands constantly after continuation bets? Is this a good player, able to trap other players? Does this guy tend to chase draws and then try to bluff?

Analyzing and exploiting situations is almost of utmost importance while playing. Let me give you an example. The great players will accumulate massive amounts of chips near the bubble, cause they know that most people just want to squeak into the money. Players like JohnnyBax and LilHoldem954 will abuse players on the bubble, accumulating stacks of chips that can be used to their advantage once they are in the money. This is all about exploiting situations.

Or how about there is a short stack at the table, and they are under the gun, with the blinds just about to go up. They push all in. You are the big blind, and it gets folded to you with A5. You need to analyze this situation. What kind of odds are you getting to call? What kind of a range does he have? Great players will make these types of calls if they are getting the right odds. In situations like these, you are often ahead with A5, although most people hate to call with this type of hands, even if they know that they are ahead.

To become a better player, you need experience and you need to go with your instincts. There is no point in developing a read on your opponent if you aren't going to use it. If your opponent pushes all-in with a small stack and you hold A5 and truly believe that you are ahead, then you must call. Even if you lose, it is all a part of becoming a better player.